The overall objective is an understanding of visual receptor and neural processes, both retinal and more central. Psychophysical experiments are proposed which, with mathematical analysis, may reveal the dynamics of the above processes. For receptors, the question to be investigated is the nature of the temporal delay, and whether it is due to diffusion, multiple stages, or some other process. A method of measuring differences in delay between different color mechanisms is the key to this investigation. Neural interactions to be studied will include the dynamics and extent of lateral inhibition and its effect on acuity, and tests of the "channel hypothesis." Lateral inhibition will be studied both with achromatic and chromatic stimuli, because there is evidence that color-opponent systems may be intimately involved with the nature of lateral inhibition. For this, both single-line and multiple-line (grating) stimuli are to be developed, with both spatial and temporal control of luminance as well as color. The "channel hypothesis" poses the possibility that the visual system does a crude Fourier analysis of the spatial frequency spectra of objects seen, somewhat in the manner of the ear on acoustic stimuli. On this basis, the perceived size of an object should be predictable in terms of its perceived spectrum. Adaptation experiments suggest that this is so. An experiment is reported which conflicts with this notion, in its simplest form. Elaboration of this work is suggested.